What do you mean, "When filling out the Schedule 1 form"? Were you in Forms mode making direct entries into Schedule 1 (1040)? Please do not do this, but work instead in Step-by-Step mode.
First, please delete anything that you entered through Forms mode, then go back and enter the 1099-G by going to Wages & Income->1099-MISC and Other Common Income->State and Local Tax Refunds on Form 1099-G
Then if it duplicates, come back and tell us.
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